The present invention provides an improved method whereby artificial insemination of turkeys and chickens is accomplished by administering concommitantly with said insemination a poultry fertility-enhancing prostaglandin (POFEN-PG).
A further aspect of the present invention is an improved method for the artificial insemination of hens whereby a semen-diluent mixture is employed in the insemination, said diluent containing a POFEN-PG.
Finally, the present invention particularly provides novel compositions of POFEN-PG's contained in poultry semen diluents and mixtures of said diluents containing a POFEN-PG with poultry semen.
The artificial insemination of poultry (e.g. turkeys and chickens) has obvious economic advantages as compared to reliance on natural insemination. In particular, the actual insemination of all egg-laying hens can be controlled and not left to the vagaries inherent in the natural process. More importantly the entire breeding stock of hens can be maintained in laying cages, rather than needing to roam about while awaiting a natural insemination. However, in view of the costs and difficulties in using artificial insemination as a method of producing fertile eggs, it has not heretofore been economically feasible in the case of chickens, and remains a costly exercise when employed commercially in turkeys.
In particular, artificial insemination in poultry requires that egg-laying capacity, fertility, and hatchability all be maintained at the high level observed in the case of successful natural insemination, and particularly be effective at maintaining fertility and hatchability for prolonged periods of time so as to reduce the number of inseminations required during the breeding season.
Accordingly, a method of artificial insemination in poultry which would not effect egg-laying capacity, while maintaining the intensity of the hens' fertility (the percentage of fertile eggs compared to total egg production), and prolonging the interval required between inseminations wherein intense fertility is observed, would increase cost efficiency of the operation. Moreover, any extended intervals between inseminations would cause a reduction in egg production losses invariably experienced each time a bird is handled and, equally importantly, reduce the number of males needed for insemination.
In order to maintain intense fertility in chicken hens, artificial insemination may be required once or twice per week during the egg laying season. See, for example, McCartney, M. G., Journal of Poultry Science 55:669-671 (1976), which described obtaining optimal fertility through artificial insemination by twice weekly inseminations with 0.05 mls. of neat semen. Further, see VanKrey, H. P., et al., Journal of Poultry Science 55:725-728 (1976) comparing insemination at nine or ten day intervals. This latter reference described the need to increase the number of spermatozoa inseminated in order to insure optimal fertility during the ten-day insemination interval. For earlier work on chicken insemination, see the semen volume and insemination schedules of Quinn, J. P. et al., J. Hered. 28:31-37 (1936), and Burrows, W. H., et al., Poultry Science 17:131-6 (1936).
As for the effect of prostaglandins on the female reproductive tract in poultry, see Day, S. A., The Role(s) of Prostaglandins in the Reproductive Physiology of the Hen, Dissertation Abstracts International 37(5):2106 (1976) which concludes that the effects of endogenous prostaglandins on the reproductive system seem to be exerted on the shell gland, a smooth muscle tissue, as opposed to those portions of the oviduct and related tissues where ovulation, fertilization, or sperm storage (i.e., the host glands) takes place.